What is the Alien Space Time. Can we ever travel in time?

The curvature of space and time caused by any form of energy, such as mass, or radiation pressure. These variables form the energy-momentum tensor and go to the Einstein equations as a source of the gravitational field. The resulting force-free curvilinear motion of bodies along geodesics is attributed to the gravitational acceleration - in this model no longer exists such a thing as a gravitational force. In an infinitesimal space portion (local map) the gravitational field has always produced the flat metric of special relativity. This is described by a constant curvature space by a factor g/c2. The curvature of world lines (motion curves in space-time) all force-free body in this section is the same space.

In many popular representations of the general relativity theory is often ignored, that not only space but also the time must be curved to create a gravitational field. That always curved space and time must be, is easy to understand intuitively: If only the curvature of space, the trajectory of a thrown stone would always be the same, no matter what initial velocity of the stone possessed, because he would always just follow the curved space. Only by the curvature of the extra time, the different trajectories arise. As part of the ART, this can be shown mathematically.

In normal, three-dimensional space is just the projection of the world lines visible on the plane of motion. The body has the velocity v, then the world line on the time axis is inclined by an angle v and that tan α = / c. The projection of the orbit becomes longer with increasing v by a factor 1 / sin α, the larger radius of curvature by the same factor 1 / sin α, the angle change is less so. The curvature (change in angle per length portion) is therefore smaller by a factor sin 2α.